The reovirus nonstructural protein, oNS, has been expressed in insect cells and purified in large quantities for structural and other studies. The 41 IJ)a protein forms oligomers (by sucrose gradient analysis), probably l2mers and some smaller forms (~3mers). The hope was to determine its oligomeric state by STEM mass analysis. Unfortunately, in the first attempt there was a lot of denatured protein and things appeared to be falling apart. Hopeft~lly, a new preparation will be better.